Answer:
The answer is: availability of complementary services
Step-by-step explanation:
The two health checkups and the gym kit are complementary services and goods to the main service Body Sync offers which is the use of the gym facilities.
Complements are goods or services consumed jointly.
Usually customers have to pay for complementary goods (e.g. coffee and sugar). When Body Sync gives those services for free it is enhancing the value of the services it offers.